Evaluation of the tip of standardized D0 gutta percha cones of four Rotary systems, by means of an endodontic ruler BUENOJuliana do Prado Tavares MELOTiago André Fontoura de KUNERTGustavo Golgo 2018 <div><p>ABSTRACT Objective : This study aimed to evaluate the D0 diameter of standardized gutta-percha cones for four mechanized systems: ProTaper Universal®, Mtwo®, Wave One® and Reciproc®. Methods: An endodontic calibrator ruler was used to measure the D0 diameter of 60 main cones of the above systems. Measurements were made according 3 scores as follows: gutta-percha cone fits exactly into the same hole as the endodontic ruler gauge (score 1), cone falls short of the ruler gauge whole size (score 2); or exceeding the ruler gauge hole size (score 3). The diameters D0 obtained were compared with the values reported by manufacturers. All data were analyzed by means of T Test, at 1% level of significance. Results: The average value measured was significantly higher than the measures established by manufacturers (p <0.001). Conclusion : The gutta-percha cones of ProTaper Universal® systems Mtwo®, Wave One® and Reciproc® were not standardized, except for R40 cone of the Reciproc® system (Reciproc®). The trend was for variation in the D0 Diameter towards increasing measurement values.</p></div>